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For over nine decades, the worlds primary standard for sorting out viscosity grades has been a document called SAE J300, Engine Oil Viscosity Classification. Originally issued in 1911, it was a simple system that arrayed engine oils according to kinematic viscosity.

As engines and oils became more complex, other properties were added to the standard. Winter grades (denoted by the letter W) made temperature-spanning multigrades possible, and the system was changed to embrace them too. Measurements were added to ensure cold cranking, pumpability, high-temperature viscosity, and ability to stand up to shearing.

Today, the once-simple document incorporates four separate viscosity measurements. And with complexity has come concern. Critics charge that J300 fails to meet consumers need for easy-to-understand information on fuel economy and cold-weather performance. Oil marketers feel boxed in by the categories, saying J300 doesnt recognize innovation, and should better accommodate advances such as high viscosity index base stocks. Heavy-duty engine builders have expressed dissatisfaction with some of its definitions, saying they need additional grades to assure they get the appropriate wear protection at high temperatures. (In the late 1990s, for example, they hoped a 35 grade could be added between the straight 30 and 40 grades, but got nowhere with the idea.)

Although he tactfully declines to take sides in the debate, Afton Chemicals Dewey Szemenyei says the issue is ripe for airing out. As chairman of SAE Internationals Technical Committee 1 on Engine Oils, he recently asked the groups Engine Oil Viscosity Classification Task Force to take a closer look at J300: What is it? What should it be? Who are its major customers? Should it stay like it is, or undergo a major transformation?

To answer some of those questions, the task force is sponsoring an Open Forum complexion Tuesday, Oct. 25, during the 2005 SAE Powertrain and Fluid Systems Conference in San Antonio, Texas. The goal, its organizers explain, is to open up J300 to scrutiny, to see what can be improved – or maybe even decide that the standard is fine and should be left alone.

The stakeholders, of course, are many. Manufacturers of passenger vehicles, heavy-duty engines, railroad, marine and aviation equipment, and small engine manufacturers all rely on J300 to specify the correct grade of oil for their equipment. Consumers follow the recommendation in their owners manuals, or have their mechanic or installer do so. Government agencies, such as the military, municipal bus fleets, and government ministries worldwide reference the standard in their procurement guidelines. The Lubricants Committee of the American Petroleum Institute relies heavily on the standard, as do oil and additive companies. Its also used to establish viscosity grade read-across guidelines.

The standard seems to be working adequately – at the moment – for most of these stakeholders except for the individual consumer, points out Andrew Jackson of ExxonMobil, who chairs the SAE task force looking at J300. Some drivers, he says, switch to inappropriate grades despite the recommendations in their owners manuals, out of habit or ignorance or convenience. The standards nomenclature – SAE 5W-30, 15W-40, 30, etc. – while meaningful to manufacturers and blenders, is misunderstood by many consumers. Some think the W stands for Wear, for example. (It doesnt; it stands for Winter.) They also dont understand that 0W and 5W might be good recommendations; theyre distrustful of such low-seeming grades.

SAE J300 has been revised many times already, so there is precedent for adding to it and revising it to suit current needs. Future needs are also worth exploring, says task force member Mike Covitch of Lubrizol. SAE J300 is very useful and serves our industry very well, he told LubesnGreases. Theres a concern though, that formulating certain popular viscosity grades will become constrained with the availability of high viscosity index base fluids, especially Gas-to-Liquid base oils. These are not a presence in the marketplace now, but they will be sometime around 2008 to 2010, and were seeing some of that now with API Group III base stocks.

Under the current viscosity classification system, he points out, the cold-cranking viscosity measurement includes a floor for each W grade, such as 5W-30 or 10W-30. With the tighter Noack volatility requirements of engine oils today, formulators can use high viscosity index base stocks to get both their viscosity and volatility in line – but then their highly sophisticated fluid may drop out of grade, and slip down to the next W level, such as 0W.

The problem comes, many say, when the consumer sees the 0W. Unfamiliar as they are with the system, they react negatively, not realizing it means the oil will operate at a lower temperature without loss of durability and often with improved fuel economy.

Some say the answer to this is to educate consumers about what the viscosity grades mean; others say that if a massive reeducation campaign is going to take place, a better system should be in place first.

Another longstanding criticism of the system is that it uses kinematic viscosity at 100 degrees C – a simple gravity-based measurement – to differentiate between viscosity grades. Thats convenient, but it is of no value in terms of evaluating wear protection under dynamic conditions like in an engine, Covitch and others say. Durability is what should be measured.

Covitch adds, Fuel economy is also an issue. To what extent can we look at J300 and give an indication of fuel economy as well?

Earlier this year, Savants Ted Selby and Mike McMillan of General Motors asked that same question, and concluded that a simple, unambiguous way of conveying J300s meaning to consumers was needed. At an SAE Open Forum in April, they proposed a triangle displaying a low-temperature figure – rather than a viscosity grade – that represented the lowest temperature at which an engine oil would flow, such as -10 degrees or -20 degrees (see page 6). It would also give numeric ratings for the oils contribution to fuel economy and durability. Such a consumer-friendly system could build on or accompany, but not replace J300, they added.

One aspect of J300 that no one seems to want to change is the pumpability measurement, which is critical for winter driving. Pumpability, the oils ability to flow despite freezing temperatures, is not the same as cold cranking, which simply measures the engines ability to turn over as the temperature drops, explains Mark Devlin of Afton Chemical, who has served on the viscosity task force for more than 10 years. For many years, the feeling has been that pumpability needs to be guaranteed at the lowest temperature the engine can start. Vehicle manufacturers want to know, is the oil pumping when the engine starts? he says. Otherwise, the running engine could be starved for oil, seize up and be ruined. So that part of J300 seems secure.

There are also some who think very little should be done to J300, including Bob Olree of General Motors. In our case, I dont see a big need to change J300, he comments. We recommend 5W-30 engine oils for almost all our vehicles, and dont use the super-low viscosity grades much, except we do recommend 0W-30 for some very low-temperature applications.

Olree has no problem with another grade being added, but were not pushing for it. Its not a burning need on our part.

Overall, J300 is a very complex system, and I prefer to make things simpler, he continued. But I still think we need to look at it and am very happy well have an open forum. Ill be interested in hearing what others have to say – and maybe theyll show me why change is needed. As Andy Jackson noted, all stakeholders and especially the engine and vehicle manufacturers will have to buy into any revision of J300, and there will also need to be a transition period from the old to the new version.

If theres going to be a revision, he cautioned, the work needs to begin now to accommodate future engine oil specifications. And the Open Forum is a good place to start – or decide not to. If we wait, by the time the next generations of passenger car and heavy-duty engine oils are being developed, we may not be able to move fast enough.

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